1. Field of the Invention
The invention relates to a filter arrangement for use with a vessel containing a pressurized fluid, and the arrangement includes a coalescing filter assembly disposable inside the vessel.
2. Background Art
Coalescing filters are used in automotive applications to remove liquids, such as water and oil, from fuel that is supplied to an engine. Typically, such filters are located downstream of a vessel or cylinder containing compressed fuel, such as natural gas, and upstream of a pressure regulator that regulates pressure of the fuel supplied to the engine. Because of the large pressure differential that may exist between the interior and exterior of the filters, the filters are typically provided with a rather thick-walled filter housing that is costly to manufacture. Because of limited available space, however, the filter housings are usually relatively small. As a result, frequent servicing of the filters is typically required to drain off coalesced liquids.
The invention addresses the shortcomings of the prior art by providing a filter arrangement including a coalescing filter assembly that may be inexpensively manufactured. Furthermore, the coalescing filter assembly of the invention reduces or eliminates the need for servicing to drain the assembly.
Under the invention, a filter arrangement for use with a vessel containing pressurized fluid includes a body engageable with the vessel. The arrangement further includes a coalescing filter assembly supported by the body such that the filter assembly is disposable inside the vessel when the body is engaged with the vessel.
Because the filter assembly is disposable inside the vessel, the filter assembly is not exposed to significant pressure differentials that may exist between the interior (P1) and exterior of the vessel (P2). Instead the pressure within the filter assembly (P3) will be substantially the same as that of the inside of the vessel (P1), with the exception of a small pressure differential between the inside of the filter (P4) and the body (P3) caused by the flow of the fuel through the filter. As a result, the filter assembly of the,invention may be less costly to manufacture than prior assemblies that must be configured to withstand large pressure differentials.
In one embodiment of the invention, the coalescing filter assembly includes a housing having a cavity, a coalescing filter disposed in the cavity for removing entrained liquid from the fluid, and a drain device in fluid communication with the cavity for draining the liquid removed by the coalescing filter from the cavity into the vessel. The drain device may include, for example, an electrically controlled valve. With such a configuration, the coalescing filter assembly may not require any servicing to drain the cavity.
The filter assembly may also include a particle filter in fluid communication with the cavity and disposed downstream of the cavity. The particle filter may be used to remove particulate from the fluid.
The filter arrangement may also include a supply valve supported by the body and in fluid communication with the coalescing filter assembly. For example, the filter arrangement may include an electrically controlled supply valve connected between the body and the coalescing filter assembly. Advantageously, the supply valve may be used to control the flow of fluid through the coalescing filter assembly.
The filter arrangement may also include valve means or a pressure regulating device disposed in the body, between the outside of the vessel and the coalescing filter. Such a device may be used to regulate outlet pressure of the vessel.
These and other objects, features and advantages of the invention are readily apparent from the following detailed description of the best modes for carrying out the invention, when taken in conjunction with the accompanying drawings.